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Old 01-16-2008, 02:20 PM
Nathan Dietsch
 
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Default Re: Why does dd take so long on my Ultra 60

Hello Angelo,

Angelo Alvarez wrote:
> I am trying to clone a 36GB Seagate ST336704LC using dd. The disk is
> starting to fail, so I want to replace it as soon as possible. At
> first I tried this:
> dd if=/dev/rdsk/c0t1dos2 of=/dev/rdsk/c0t0d0s2 bs=256k.
> After about 4 hours, I got tired of waiting and killed the process
> (output showed 97740+0 records in and 97740+0 records out. So after
> reading several posts regarding block size, I used a bs=8192k. Well,
> here I am about 3.5 hours later and it's still going. This system's
> SCSI card, as I understand it, has a burst transfer rate of 40MB/s.
> The hard drives are capable of 27MB/sec at a minimum. I have cloned
> other Ultra 60's with 36GB drives and I don't remember the process
> taking nearly as long. What could be the problem? Is it the hard
> disk I am cloning?


I would check /var/adm/messages, you may be coming up against a block
that just simply can't be read and getting SCSI errors, these will show
up in the above mentioned log normally.

I would copy the file systems over individually using tar or cpio to
help narrow down where the problem is on the disk and save what data can
be saved.

I hope this helps.

Regards,

Nathan Dietsch
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